1. Field
Apparatuses consistent with exemplary embodiments relate to electromagnetic wave oscillators each having a multi-tunnel and electromagnetic wave generating apparatuses including the electromagnetic wave oscillators, and more particularly, to electromagnetic wave oscillators for oscillating an electromagnetic wave in a terahertz band and electromagnetic wave generating apparatuses including the electromagnetic wave oscillators.
2. Description of the Related Art
A frequency band of terahertz (1012 Hz) between a microwave frequency band and an optical frequency band is expected to be a frequency band that is very significant in the fields of molecular optics, biophysics, medicine, spectroscopy, imaging, security, and the like. However, despite the significance of the terahertz band, the development of terahertz oscillators or amplifiers that generate terahertz waves is not sufficient due to physical and engineering limitations. As several new theories and a micro-processing technology have been developed, the development of terahertz oscillators or amplifiers has been recently attempted.
For example, several approaches, such as increasing frequencies of several oscillators in an existing micro-wave band, or changing an operational frequency into a terahertz band by using an optical device, such as a semiconductor laser or a femtosecond laser have been tried. In addition, a variety of schemes for making small-size terahertz oscillators by using a three-dimensional (3D) micro-structure manufactured using micro electro mechanical system (MEMS) technology have been recently suggested.
Backward wave oscillators are an example of terahertz oscillators using MEMS technology. A backward wave oscillator is a kind of interaction circuit that forms an electron beam path in a cavity for resonating an electromagnetic wave in order to oscillate a terahertz wave by interacting an electron beam emitted from an electron gun with the electromagnetic wave. A mechanism for converting energy of the electron beam to electromagnetic wave energy by interaction between the electron beam and the electromagnetic wave is significant in the terahertz interaction circuit.